Metallic composition



Patented May 23, 19 39 Franz R. Hensel, Indianapolis, Ind., assignor to P. R. Mallory & 00., Inc., Indianapolis, Ind., a corporation of Delaware No Drawing. Application October 2, 1937, Serial No. 167,023

Claims.

This invention relates to a metallic composition and the manufacture thereof.

It is an object of the invention to provide a V material which will have .useful properties for many applications and which will be particularly suitable for electrical contacting members, be-

cause it will provide/low contact resistance and long life under arcing" conditions such as are encountered in electrical contacts used for making and breaking electrical circuits.

It is a further object of the invention to pro-- vide a material which .will be useful for bearing purposes.

It is a further object of the invention to produce a new metallic composition and combinations of metallic elements the production of which. heretofore has not been practicable.

Other objects of the invention will be apparent from the following description taken in connection with the appended claims.

The present invention comprises the combination of elements, methods of manufacture, and the product hereinafter set forth, the scope of the invention being indicated in the appended claims.

While a preferred embodiment of the invention is described herein, it is contemplated that considerable variation may be made in the method of procedure and the combination of elements without departing from the spirit of the invention.

The invention contemplates the provision of, a metallic. body consisting of elements which ithas been impossible to alloy by the standard methods. of the prior art. The new metallic composition comprises the combination of such elements as cobalt and nickel with metals which have a low-melting point and also a low boiling point, such as cadmium and zinc, and silver.

The complete composition may contain the combined ingredients in the following ranges of proportions:

Percent Metal of the nickel-cobalt group 25 to 90 Metal of the cadmium-zinc group i to -30 Silver in theleast useful amount; to 70 The selection of the exact composition to be i tion contemplated. The following alloy com-. positions are therefore given as specific examples of preferable proportions for certain specific purposes: 1 Percent 5 a. Metal of the nicker-cobalt group 70 Metal from the group cadmium and zinc 28 Silver 2 b. Metal of the nickel-cobalt group 50 Metal comprising the group of cadmium l0 and zinc i g 10 Silver--- 40 0. Metal of the nickel-cobalt group 30 Metal comprisingthe group of cadmium and zinc 10 15 Silver 60 d. Metal of the nickel-cobalt group 50 Metal comprising the group of cadmium and zinc 25 Silver 25 e. Metal of the nickel-cobalt group; 30

Metal comprising the group of cadmium and zinc I I Silver 45 f. Nickel C) 60 25 Cadmium 10 'Silver g. Nickel 25 Cadmi m 5 Silver '70 30 While the alloy described in a has been' found very useful as a high grade bearing material, the balance of the alloys have been particularly developed to produce an electrical contacting material. By varying theproportions of the nickel or cobalt, the cadmium zinc group and the silver, the material can be adjusted for serving different contact purposes.

In certain cases,-for instance, it is necessary 40 to have non-sticking properties and a higher percentage of cadmium is found advisable. This cadmium content also will' tend to lower the contact resistance. In other applications, it might be desirablepto have a high, specific conductivity and thereforea high silver content is desirable; in other applications the cheapness of the material isthe outstanding factor and the contact applications are not extremely severe. For such purposes, material high in a 50 stantial quantities of silver metal taken from the nickel-cobalt group is used because this will cheapen the contact.

Furthermore, the selection of thespecific composition depends on the type of manufacturing procedure that is used. If, for instance, the material must be Worked into strips or sheets, a

certain ratio of the nickel-cobalt metal, the

of silver powder compressed and sintered in a reducing atmosphere or in vacuum, then a certain weight of cadmium is placed on top of this mixture and soaked into the mixture by capillary action. The .product obtained is very homogeneous.

In producing materials which contain subor cobalt metal and a metal of the nature of cadmium, I have found it advisable to mix all powders together and compress them either at room or elevated temperatures. If I compress at elevated temperatures a denser product is produced because at such elevated temperatures the yield point of the powders is lowered and more plastic flow isobtained, which reduces greatly the porosity of the pressed sintering the, metal composition I may vary the temperature of sintering and the time of sinter-. ing in order to produce the desired results. If,

. for instance, I have silver and cadmium present,

I may sinter the material in such a way that all cadmium will alloy with the silver and form a silver-cadmium alloy which is mixed with the nickel. It is also possible, however, to carry on the sintering process only so ,far that part of the cadmium is left in the free condition, while another part combines with the silver. Accordingly, the contact behavior will be different. Cad- 'mium which is left present as free cadmium will have a stronger tendency to evaporate than cadmium which has been alloyed with the silver.

In experimenting with the above mixtures, I have made a complete microscopical study and in addition to nickel body. In subsequently from such a study, it can be found out definitely what times and temperatures of sintering must be employed for different size pieces, to obtain the desired properties.

In order to process the metallic composition of the present invention, it is possible to vary the mechanical and heat treatments. For instance, after the material has been pressed and sintered, it may be re-pressed and re-sintered, or-it may be forged, rolled and swaged and then from such swaged strips or wires, contact plates or contact rivets might be procured which are fastened to some sort of a support by either a brazing or a welding method and used in electrical equipment as contacting elements.

vWhile the present invention asto its objects and advantages has been described herein as carriedout in specific embodiments thereof, it is not desired to be limited thereby, but it is intended to cover the invention broadly within .the spirit and scope of the appended claims.

. What is claimed is:

l. A metal composition of nickel, cadmium and silver, said nickel comprising to 90% of said composition, said cadmium comprising 1 to of said composition, balance substantially all silver.

2. An electrical contacting member formed of a metal composition composed of a sintered mixture of powders of metal selected from the group consisting of nickel and cobalt, metal selected from the group consisting of cadmium and zinc, and silver, said nickel-cobalt group metal being present in proportions of 25 to 90%, said cadmium-zinc group metal being present in proportions of l to 30% and said silver being present in proportions ranging from the least useful amount to 70%.

3. An electrical contacting member formed of a metal composition pf nickel, zinc and silver, said nickel comprising 25 to 90% of said composition, said zinc comprising 1 to 30% of said composition, balance substantially all silver.

4. An electrical contacting'member formed of a metal composition of cobalt, cadmium and silver, said cobalt comprising 25 to 90% of said composition, said cadmium comprising 1 to 30% of said composition, balance substantially all silver.

5. An electrical contacting member formed of a metal composition of cobalt, zinc and silver,

said cobalt comprising 25 to 90% of said composition, said zinc comprising 1 to 30% of said composition, balance substantially all silver.

FRANZ R. HENSEL. 

